System and method to determine second ECU state using shared sensor in a dual ECU system

Abstract

Technical solutions are described for a system and method for determining status of an electronic control unit (ECU) in a dual-ECU system. The method includes: determining, by a first ECU, a pin state of an communications terminal connected to a sensor; powering the sensor by a second ECU; and determining, by the first ECU, a status of the second ECU based on the pin state of the communications terminal. The first ECU may determine the second ECU as being nonresponsive via a communications interface, and the first ECU may determine the status of the second ECU in response to determining the second ECU being nonresponsive via the communications interface. The first ECU may determine the status second ECU as being one of powered-on and non-responsive, powered-on and functioning, or powered-off, based on the pin state of the communications terminal.

What is claimed is: 
     
       1. A method of determining status of an electronic control unit (ECU) in a dual-ECU system, comprising:
 providing a first ECU having a first communications terminal in electrical communications with a sensor and having a pin state representing data from the sensor; 
 reading, by the first ECU, the data from the sensor based on the pin state of the first communications terminal; 
 reading, by a second ECU, the data from the sensor via a second communications terminal in electrical communications with the sensor; 
 powering the sensor by the second ECU, thereby biasing a voltage of the first communications terminal and the second communications terminal to a logic level high condition; and 
 determining, by the first ECU, a status of the second ECU based on the pin state of the first communications terminal, and 
 wherein the sensor is physically independent of each of the first ECU and the second ECU. 
 
     
     
       2. The method of  claim 1 , further comprising:
 determining, by the first ECU, the second ECU being nonresponsive via a communications interface, wherein the communications interface is independent of the first communications terminal, and
 wherein the determining the status of the second ECU is performed in response to determining the second ECU being nonresponsive via the communications interface. 
 
 
     
     
       3. The method of  claim 1 , wherein the pin state representing data from the sensor includes at least one of a logic level high condition and a logic level low condition, and
 wherein the method further comprises: determining the status of the second ECU based on the pin state of the first communications terminal remaining at a given one of the logic level high condition or the logic level low condition and for a predetermined period of time. 
 
     
     
       4. The method of  claim 1 , further comprising:
 verifying a sensor signal protocol data based on the pin state of the first communications terminal; and
 determining, by the first ECU, if the sensor signal protocol data passes a protocol check, 
 wherein determining the status of the second ECU depends on the sensor signal protocol data not passing the protocol check. 
 
 
     
     
       5. The method of  claim 1 , further comprising:
 determining, by the first ECU, the pin state of the first communications terminal toggling between a logic level high condition and a logic level low condition by not remaining at a given one of the logic level high condition or the logic level low condition for a predetermined period of time; and 
 determining, by the first ECU, the status of the second ECU as powered-on and functioning in response to determining the pin state of the first communications terminal toggling between the logic level high condition and the logic level low condition. 
 
     
     
       6. The method of  claim 1 , further comprising:
 determining, by the first ECU, the pin state of the first communications terminal remaining at a logic level high condition for a first predetermined period of time; and 
 determining, by the first ECU, the status of the second ECU as powered-on and non-responsive in response to determining the pin state of the first communications terminal remaining at the logic level high condition for the first predetermined period of time. 
 
     
     
       7. The method of  claim 6 , further comprising: performing, by the first ECU, a first control action in response to determining the status of the second ECU as powered-on and non-responsive, the first control action including, at least, initializing communications with the sensor. 
     
     
       8. The method of  claim 1 , further comprising:
 determining, by the first ECU, the pin state of the first communications terminal remaining at a logic level low condition for a second predetermined period of time; and 
 determining, by the first ECU, the status of the second ECU as powered-off in response to determining the pin state of the first communications terminal remaining at the logic level low condition for the second predetermined period of time. 
 
     
     
       9. The method of  claim 8 , further comprising: performing, by the first ECU, a second control action in response to determining the status of the second ECU as powered-off. 
     
     
       10. The method of  claim 9 , wherein the second control action includes, at least, providing power to the sensor and initializing communications with the sensor. 
     
     
       11. A method of determining status of an electronic control unit (ECU) in a dual-ECU system having a first ECU and a second ECU, comprising:
 reading, by the first ECU, sensor data from a sensor via a first communications terminal in electrical communications with the sensor; 
 reading, by the second ECU, the sensor data from the sensor via a second communications terminal in electrical communications with the sensor; 
 powering the sensor by the second ECU, thereby biasing a voltage of each of the first communications terminal and the second communications terminal to a logic level high condition, wherein the sensor is physically independent of each of the first ECU and the second ECU; 
 determining, by the first ECU, the second ECU being nonresponsive via a communications interface, wherein the communications interface is independent of each the first communications terminal and the second communications terminal; 
 determining, by the first ECU and in response to determining the second ECU being nonresponsive, a sensor signal protocol data based on a pin state of the first communications terminal; 
 determining, by the first ECU, if the sensor signal protocol data passes a protocol check; 
 determining, by the first ECU and in response to determining the sensor signal protocol data not passing the protocol check, a pin state of the first communications terminal; 
 determining, by the first ECU and in response to determining the sensor signal protocol data not passing the protocol check, a status of the second ECU based on the pin state of the first communications terminal, wherein the pin state includes at least one of the first communications terminal remaining at a given logic level condition for a predetermined period of time or the first communications terminal toggling between a logic level high condition and a logic level low condition by not remaining at a given one of the logic level high condition or the logic level low condition for the predetermined period of time, 
 wherein determining the status of the second ECU includes determining the status of the second ECU as powered-on and functioning in response to determining the pin state of the first communications terminal toggling between the logic level high condition and the logic level low condition, 
 wherein determining the status of the second ECU includes determining the status of the second ECU as powered-on and non-responsive in response to determining the pin state of the first communications terminal remaining at the logic level high condition for a first predetermined period of time, 
 wherein each of the first ECU and the second ECU are configured to communicate with the sensor using a Single Edge Nibble Transmission (SENT) protocol; 
 wherein determining the status of the second ECU includes determining the status of the second ECU as powered-off in response to determining the pin state of the first communications terminal remaining at the logic level low condition for a second predetermined period of time; 
 performing, by the first ECU, a first control action in response to determining the status of the second ECU as powered-on and non-responsive, the first control action including, at least, initializing communications with the sensor; and 
 performing, by the first ECU, a second control action in response to determining the status of the second ECU as powered-off, wherein the second control action includes, at least, providing power to the sensor and initializing communications with the sensor. 
 
     
     
       12. A system for determining status of an electronic control unit (ECU) in a dual-ECU system, comprising:
 a sensor having a sensor output pin; 
 a first ECU having a first communications terminal in electrical communication with the sensor output pin and having a pin state representing sensor data from the sensor, the first ECU being configured to read the sensor data from the sensor based on the pin state of the first communications terminal; and 
 a second ECU having a second communications terminal in electrical communication with the sensor output pin, the second ECU being configured to read the sensor data from the sensor based on a pin state of the second communications terminal, the second ECU providing power to a sensor power rail and biasing a voltage of the first communications terminal and the second communications terminal to a logic level high condition, and 
 wherein the first ECU is configured to determine a status of the second ECU based on the pin state of the first communications terminal. 
 
     
     
       13. The system of  claim 12 , further comprising: a communications interface between the first ECU and the second ECU and providing communications therebetween, and
 wherein the first ECU is configured to determine the status of the second ECU in response to determining the second ECU being nonresponsive via the communications interface. 
 
     
     
       14. The system of  claim 12 , wherein the first ECU is configured to determine the status of the second ECU based on the pin state of the first communications terminal remaining at a given logic level condition for a predetermined period of time. 
     
     
       15. The system of  claim 12 , wherein each of the first ECU and the second ECU are configured to communicate with the sensor using a Single Edge Nibble Transmission (SENT) protocol. 
     
     
       16. The system of  claim 12 , wherein the first ECU is configured to determine the pin state of the first communications terminal toggling between a logic level high condition and a logic level low condition by not remaining at a given one of the logic level high condition or the logic level low condition for a predetermined period of time, and
 wherein the first ECU is configured to determine the status of the second ECU as powered-on and functioning in response to determining the pin state of the first communications terminal toggling between the logic level high condition and the logic level low condition. 
 
     
     
       17. The system of  claim 12 , wherein the first ECU is configured to determine the pin state of the first communications terminal remaining at a logic level high condition for a first predetermined period of time, and
 wherein the first ECU is configured to determine the status of the second ECU as powered-on and non-responsive in response to determining the pin state of the first communications terminal remaining at the logic level high condition for the first predetermined period of time. 
 
     
     
       18. The system of  claim 17 , wherein the first ECU is configured to perform a first control action in response to determining the status of the second ECU as powered-on and non-responsive, the first control action including, at least, initializing communications with the sensor. 
     
     
       19. The system of  claim 12 , wherein the first ECU is configured to determine the pin state of the first communications terminal remaining at a logic level low condition for a second predetermined period of time, and
 wherein the first ECU is configured to determine the status of the second ECU as powered-off in response to determining the pin state of the first communications terminal remaining at the logic level low condition for the second predetermined period of time. 
 
     
     
       20. The system of  claim 19 , wherein the first ECU is configured to perform a second control action in response to determining the status of the second ECU as powered-off, wherein the second control action includes, at least, providing power to the sensor and initializing communications with the sensor.